When human cartilage is congenitally deficient or becomes damaged or deficient in the course of lifetime, usually the cartilage is not regenerated. For treating diseases of such human cartilage, a method has been used in which a cartilage tissue is taken from a site of a patient and transplanted into the deficient site of the patient. However, this method has problems that the donor site and the amount of the tissue that can be taken are limited. Then, methods in which a part of autologous chondrocytes is taken, cultured ex vivo and returned to the deficient site have been developed (Non-Patent Documents Nos. 1-4) and applied clinically (Non-Patent Documents Nos. 5, 6 and 7).
However, these methods using chondrocytes have two problems: invasion into the donor site and retention of the shape of a regenerated tissue for a long time. The first one (invasion) is a problem that the donor site from which a cartilage tissue has been taken for culture may result in deformities, such as defect or recess, or dysfunction. The second one (retention of the shape for a long time) is a problem whether a tissue regenerated with cultured cartilage can retain its shape for a long time without being absorbed.
In order to solve these problems, other sources of chondrocytes have been sought for. That is, an idea has been contemplated in which cells other than chondrocytes are differentiated ex vivo into chondrocytes and returned into the living body. Examples of these cells include embryonic stem cells, mesenchymal stem cells, cells derived from the synovial membrane of knee joint, and adipocytes (Non-Patent Documents Nos. 1-4). All of these cells have been confirmed to differentiate into chondrocytes. However, clinical application of embryonic stem cells is difficult from an ethical viewpoint; collecting mesenchymal stem cells or cells derived from the synovial membrane of knee joint is difficult and highly invasive; differentiating adipocytes into chondrocytes is still under development; and mesenchymal stem cells have the problems of invasion and differentiation efficiency. Thus, any of these cells has not reached the stage of clinical application.
To date, in vivo and ex vivo researches have confirmed that perichondrium forms cartilage (Non-Patent Documents Nos. 8-10). In those researches, perichondrium is transplanted as a mass without being isolated. Such transplant is far from clinical application.
[Non-Patent Document 1]
    van Osch G J et al, Plast Reconstr Surg 107:433-440 (2001)[Non-Patent Document 2]    Brittberg et al, The New England Journal of Medicine 331:889-895 (1994)[Non-Patent Document 3]    Ting et al, Annals of Plastic Surgery 40:413-421 (1998)[Non-Patent Document 4]    Rodriguez et al, Plastic and Reconstructive Surgery 103:1111-1119 (1999)[Non-Patent Document 5]    Ochi M et al, J Bone Joint Surg 84:571-578 (2002)[Non-Patent Document 6]    Yanaga H et al, Aesth Plast Surg 28: 212-221 (2004)[Non-Patent Document 7]    Yanaga H et al, Plast & Reconstr Surg 117: 2019-30 (2006)[Non-Patent Document 8]    Ove Engkvist et al., Scand J Plast Reconst Surg. 1979, 13; 275-280[Non-Patent Document 9]    Ove Engkvist et al., Scand J Plast Reconst Surg. 1979, 13; 371-376[Non-Patent Document 10]    Duynstee et al., Plasr and Reconst Surg. 2002, 110(4). 1073-1079[Patent Document 1]    Japanese Unexamined Patent Publication No. 2005-511083[Patent Document 2]    Japanese Unexamined Patent Publication No. 2003-51875[Patent Document 3]    Japanese Unexamined Patent Publication No. 2005-500085[Patent Document 4]    Japanese Unexamined Patent Publication No. 2001-103965